push(key, value, index1, key1, index2, key2, index3, key3);
push(key, value, index1, key1, index2, key2, index3, key3);
push(key, value, index1, key1, index2, key2, index3, key3); return null;
push(key, value, index1, key1, index2, key2, index3, key3); return null;
push(key, value, index1, key1, index2, key2, index3, key3);
push(key, value, index1, key1, index2, key2, index3, key3); return null;